(2S,3R)-3-[(2S,3R,4R,5R,6R)-3-Acetylamino-5-benzyloxy-6-benzyloxymethyl-4-((2R,3R,4S,5S,6R)-3,4,5-tris-benzyloxy-6-benzyloxymethyl-tetrahydro-pyran-2-yloxy)-tetrahydro-pyran-2-yloxy]-2-tert-butoxycarbonylamino-butyric acid methyl ester